Particularly in the food industry there is a need to control consistency, taste, texture and mouthfeel of compositions. A broad range of thickeners is known in the art and conventionally employed for increasing the consistency of various food compositions. Well-known in this respect are starch and gellable biopolymers or gums. Examples of the latter group are gelatin, agar, carrageenans, pectins, alginates, xanthan, locust bean gum et cetera.
Each of the agents above has its own disadvantages limiting its use for certain applications:
The application of starch may result in a sticky mouthfeel and/or characteristic smell or flavour of starch, while biopoloymers or gums have a tendency to produce slimy or slightly gellified foodstuffs. Furthermore, most gums are rather expensive ingredients. The non-vegetable origin of biopolymers such as, for example, gelatin is another reason for making those biopolymers a less desirable food ingredient.
Vegetable purees that can be used to thicken food compositions have been described as alternatives for gellable biopolymers such as gums. JP 57/202257 discloses that soups, curry's, stews, sauces and the like may be thickened by the incorporation of smashed, steamed and homogenised vegetables, being rich in starch. The homogenisation is carried out, according to this invention, at a pressure between 30 to 150 bar. WO99/65328 describes a vegetable puree that is used to thicken food products, wherein the vegetable puree is prepared from homogenised vegetables being low in starch. Homogenisation is preferably carried out at 100 to 200 bar. WO96/11588 reports that tomato-based products of thick consistency can be obtained by subjecting a tomato paste to a high pressure shear field (i.e. high pressure homogenisation) and adding a source of pectinmethylesterase (e.g. raw vegetables or fruits) to the paste. These documents teach a processes for thickening a food product which overcome some of the problems described above but require some kind of pressure treatment (high pressure homogenisation) for obtaining the thickening effect.
U.S. Pat. No. 4,547,375 reports that hot break tomato pastes can be thickened if onions are added to the paste. The onions are reported to lose their gel-inducing (thickening properties) if they are pretreated at temperatures greater than 71° C.